Various electrical connectors are formed from sheet metal and include a receptacle portion having a bottom wall and a pair of upstanding side walls terminating in end portions turned inwardly over the bottom wall. The receptacle is adapted to receive a plug terminal such as a flat male tab. A resilient tongue is formed from the base and has a tang which cooperates with a cut-out formed in the flat male tab in order to secure the tab or plug terminal against removal from the receptacle.
The receptacle often is inserted into a duct-shaped housing and locked therein for receiving the plug terminal. The housing may include a cam actuator for engaging the receptacle tongue to bend the tongue in response to pulling on the housing, to release the plug terminal.
Such electrical connectors often are used in electrical circuits associated with machinery which are subjected to vibrations and other forces. In such environments, the electrical connector affords good electrical contact and, at the same time, it provides a releasable connection between the plug terminal and the receptacle. Examples of such connectors are shown in U.S. Pat. Nos. 4,550,963 to Moors, dated Nov. 5, 1985; 4,579,409 to Enneper et al., dated Apr. 1, 1986; 4,632,483 to Verin, dated Dec. 30, 1986; 4,542,948 to Alonso et al., dated Sept. 24, 1985; 4,690,478 to Rahrig et al., dated Sept. 1, 1987; and 4,458,971 to D'Urso et al., dated July 10, 1984.
One of the problems with electrical connectors of the above type is over-stressing of the tongue which locks the plug terminal in the receptacle. The tongue often is unitarily formed or stamped out of the base or bottom wall of the receptacle so as to be resilient to provide for locking and ready release of the plug terminal. In order to be releasable by the housing, the tongue projects below the bottom wall of the receptacle for engagement by cam means on the housing to move the tongue out of locking engagement with the terminal. During manufacturing, shipping, handling or the like, i.e., prior to insertion into the housing, the resilient tongue cannot be bent past a given point or else it will become over-stressed and loose its resiliency and even may be deformed. If the tongue is bent too far, its locking function is less effective and it may be bent so far as to be completely ineffective. In addition, even a small degree of deformation will increase the insertion force on the plug terminal. This invention is directed to solving this problem in a very simple and efficient manner.